The present invention relates to the field of transparent materials, in particular transparent materials whose reflection is reduced.
With many transparent materials, in particular transparent materials based on plastic, such as for instance polycarbonate etc., the difficulty arises that these have, in part, unwanted reflection properties, which hamper or even render impossible their use in many applications.
Numerous attempts were thus undertaken to design transparent materials to be less reflective, in particular by applying further layers.
To this end, it was proposed for instance, by a so-called “flower-like alumina” layer, to reduce the reflection (see Yamaguchi et al, Journal of Sol-Gel Science & Technology, 2005, 33, 117-120). This procedure nevertheless requires a tempering step with increased temperatures (approx. 400° C.).
Other proposed coatings include multi-layer systems with changing refractive indices, e.g. multi-layer systems made of SiO2 and TiO2. Tempering steps, generally at temperatures above 400° C., are also needed here (see M. Walther, OTTI-Seminar Regensburg, September 2005). Other systems use layers made of TiO2 and MgF2 (see EP 564 134 B1), in which additional fluorocarbon resins are provided. This system is in turn disadvantageous in respect of poor applicability.